Rapid prototyping and fabrication method for 3-D food objects

ABSTRACT

A freeform fabrication method for making a three-dimensional food object from a design created on a computer, including: (a) providing a support member by which the object is supported while being constructed; (b) operating a material dispensing head for dispensing a continuous or intermittent strand of food composition in a fluent state; this food composition including a liquid ingredient and a primary body-building food material and the dispensed food composition having a rigidity and strength sufficient for permitting the food composition to be built up layer by layer into a three-dimensional shape in a non-solid state; and (c) operating control devices for generating control signals in response to coordinates of the object design and controlling the position of the dispensing head relative to the support member in response to the control signals to control dispensing of the food composition to construct a 3-D shape of this object. The method optionally includes an additional step of applying a heat treatment to the 3-D shape after this 3-D shape is constructed. This method can be used to form an intricate shape of a cake mix, which is then baked in an oven. It can also be used to form a custom-designed decorative shape on the top surface of a pre-made cake.

FIELD OF THE INVENTION

This invention relates generally to a layer manufacturing method thatuses a food composition for producing a complex-shape three-dimensional(3-D) food object, such as a custom-designed birthday cake. This methodinvolves freeform fabrication of a food object in a layer-by-layermanner without object-specific tooling (mold, template, or shaping die)or human intervention. Specifically, the food composition in individuallayers of a multi-layer object, after being dispensed from a nozzle anddeposited onto a support member, is in a physical state that is notfully solidified (e.g., still containing some substantial amount ofwater, cooking oil, egg fluid, syrup, liquid chocolate, icing, or acombination thereof). In such a non-solid state, individual layers areof sufficient rigidity and strength to support the weight ofsubsequently deposited layers to substantially maintain the shape anddimension of an intended 3-D shape while being fabricated.

BACKGROUND OF THE INVENTION

The last decade has witnessed the emergence of a new frontier in themanufacturing technology, commonly referred to as solid freeformfabrication (SFF) or layer manufacturing (LM). A LM process typicallyinvolves representing a 3-D object with a computer-aided design (CAD)geometry file. The file is then converted to a machine control commandand tool path file that serves to drive and control a part-building tool(e.g., an extrusion head) for building parts essentially point by pointand layer by layer. The LM processes were developed primarily for makingmodels, molds and dies, and prototype parts for industry uses. They arecapable of producing a freeform solid object directly from a CAD modelwithout part-specific tooling or human intervention. A SFF process alsohas potential as a cost-effective production process if the number ofparts needed at a given time is relatively small. Use of SFF couldreduce tool-making time and cost, and provide the opportunity to modifytool design without incurring high costs and lengthy time delays. A SFFprocess can be used to fabricate certain parts with a complex geometrywhich otherwise could not be practically made by traditional fabricationapproaches such as machining.

Examples of SFF techniques include stereo lithography (SLa), selectivelaser sintering (SLS), 3-D printing (3-DP), inkjet printing, laminatedobject manufacturing (LOM), fused deposition modeling (FDM),laser-assisted welding or cladding, shape deposition modeling (SDM), toname a few. There are several shortcomings associated with these SFFtechniques. In most of these techniques, for instance, the fabricationof a 3-D object either requires the utilization of expensive anddifficult-to-handle materials or depends upon the operation of heavy,complex and expensive processing equipment. For example, thephoto-curable epoxy resin used in the stereo lithography process cancost up to US$300 per pound. Melting of metallic, ceramic, and glassmaterials involves a high temperature and could require expensiveheating means such as an induction generator or a laser. Thermoplasticsalso require a moderately high temperature (normally in the range of140° C. to 380° C.) to reach a low-viscosity state for processing. Mostimportantly, most of these prior-art techniques can not be used tofabricate edible food items like cakes. All these layer manufacturingtechniques require that, in a layer-additive fabrication process, alayer be solidified to become a solid before another layer is built.Most of these prior-art LM techniques are not capable of fabricatingmulti-material or multi-color objects.

Other shortcomings of the prior-art SFF techniques are brieflysummarized as follows: The FDM process (e.g., U.S. Pat. No. 5,121,329;1992 to S. S. Crump) operates by employing a heated nozzle to melt andextrude out a material such as nylon, ABS plastic(acrylonitrile-butadiene-styrene) and wax. The build material issupplied into the nozzle in the form of a rod or filament. The filamentor rod is introduced into a channel of a nozzle inside which therod/filament is driven by a motor and associated rollers to move like apiston. The front end, near a nozzle tip, of this piston is heated tobecome melted; the rear end or solid portion of this piston pushes themelted portion forward to exit through the nozzle tip. The nozzle istranslated under the control of a computer system in accordance withpreviously sliced CAD data to trace out a 3-D object point by point andlayer by layer. This process has a drawback that it requires a separateapparatus to pre-shape a build material into a precisely dimensioned rodor filament form. The re-melting of this rod or filament in a FDM nozzlerequires additional heating elements placed around or inside the body ofthe nozzle. Furthermore, this process obviously is not capable offabricating food objects.

Additional FDM-type processes can be found in U.S. Pat. No. 5,503,785(Apr. 2, 1996) issued to Crump, et al., U.S. Pat. No. 5,866,058 (Feb. 2,1999) to Batchelder and Crump, U.S. Pat. No. 5,939,008 (Aug. 17, 1999)to Corn, et al., U.S. Pat. No. 5,968,561 (Oct. 19, 1999) to Batchelder,et al., U.S. Pat. No. 5,340,433 (Aug. 23, 1994) to Crump, U.S. Pat. No.5,738,817 (Apr. 14, 1998) to Danforth, et al., and U.S. Pat. No.5,900,207 (May 4, 1999) to Danforth, et al. In these latter two patents,a FDM process is disclosed to fabricate a ceramic object from a mixtureof ceramic particles dispersed in a binder. The mixture is made into afilament or rod form which is fed into a nozzle in which the binder ismelted to make the mixture in a fluent paste state. Upon discharge fromthe nozzle, the binder is solidified to hold the ceramic powder in adesired shape (in which all ingredients are now solids). The binder islater burned off and the remaining ceramic “green” body is subjected toa high temperature sintering treatment to produce a useful ceramicarticle.

A particularly useful SFF technique is based on extrusion ofheat-meltable materials or thermoplastics. In principle, a bulk quantityof materials (thermoplastics and wax) can be melted and directlytransferred to a dispensing nozzle for deposition; it does not requirethe preparation of a raw material to a special shape followed byre-melting. One example of an extrusion-type (but not based on the LM orSFF approach) is given in U.S. Pat. No. 4,749,347 (Jun. 7, 1988) issuedto Valavaara. Extrusion-based SFF processes can be found in U.S. Pat.No. 5,141,680 (Aug. 25, 1992) to Almquist and Smalley, U.S. Pat. No.5,303,141 (Apr. 12, 1994) and 5,402,351 (Mar. 28, 1995) both toBatchelder, et al., and U.S. Pat. No. 5,656,230 (Aug. 12, 1997) toKhoshevis. In these examples, the starting material is heated to becomea melt and then transferred to a dispensing head by using a gear pump, apositive-displacement valve, an air-operated valve, or an extruder. Thenozzle also must be heated to maintain the material in the molten stateprior to being extruded out for deposition.

Examples of extrusion-based SFF techniques using thermosetting resinsare given in U.S. Pat. No. 5,134,569 (Jul. 28, 1992) to Masters and U.S.Pat. No. 5,204,124 (Apr. 20, 1993) to Secretan and Bayless. Both systemsrequire the use of an ultra-violet (UV) beam or other high energysources to rapidly cure a thermosetting resin. Photo-curable or fastheat-curable resins are known to be expensive and the curing processeshave very limited processing windows; curing of these materials has beeninconsistent and difficult and the results have not been veryrepeatable. Obviously, one would not use a thermosetting resin formaking a cake.

An extrusion-based SFF process requires the extruded material quicklysolidify to become a solid so that it can support its own weight andother layers that are subsequently deposited thereon withoutexperiencing a significant deformation or shape change. This conditioncan be readily met with heat-meltable or thermoplastic materials byrapidly cooling the dispensed materials below their melting points. Inthe present invention, a food composition used in an extrusion type SFFprocess remains in an essentially non-solid state (e.g., a cake mix orother food paste). The food composition in a layer does not need tobecome a solid before a subsequent layer is deposited onto this layer.The only requirement imposed on the physical state of the foodcomposition of a layer is that it has sufficient rigidity and strengthto support its own weight and the weight of subsequent layers. Theprocess does not require either a high energy source (like in the caseof UV-curable resins) to achieve a solidification state, or a greatamount of heat energy to melt the material and then a cooling means tohelp solidify the material (like in the case of thermoplastics).Instead, the food material composition is formulated to contain a liquidingredient (such as water) which acts to make the food composition in afluent state to facilitate dispensing from a nozzle. This liquidingredient does not have to be removed during the object-buildingprocedure. Because there is no need to solidify individual layers beforesubsequent layers are deposited, solidification of these layers wouldnot become a constraining factor in limiting the speed of objectfabrication. This is in contrast to essentially all conventionalfreeform fabrication processes in which individual layers must besolidified prior to deposition of a subsequent layer. The presentlyinvented freeform fabrication method can be used to make a brilliant 3-Ddecorative icing/topping shape on a baked cake. The method may also beused to form a cake mix into a desirable shape before being baked in aoven; in this case, the final shape could be different from the originalshape.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a layer-additive methodfor fabricating a three-dimensional food object in an essentiallylayer-by-layer manner.

Another object of the present invention is to provide an improved methodthat can automatically reproduce a 3-D food object directly from acomputer-generated data file representing this object.

Yet another object of the present invention is to provide a method forproducing a 3-D food object of an intricate shape without the use of anobject-specific tooling or human intervention.

A further object of the present invention is to provide a simple andcost-effective freeform fabrication method for building a 3-D foodobject without using heavy and expensive equipment.

Still another object of the present invention is to provide a method forproducing a multi-color 3-D food object of an intricate shape in anautomated fashion.

BRIEF SUMMARY OF THE INVENTION

The above objects are realized by a method which begins with creation ofa computer-aided design (also referred to as a drawing, an image, or ageometry representation) of a three-dimensional food object. The methodthen involves providing a support member by which the object issupported while being constructed. It also involves operating a materialdispensing head (nozzle) for dispensing a strand of food composition ina fluent state. This food composition includes a liquid ingredient thathelps to make the food composition in a fluent state while stillresiding in a chamber of the dispensing head. After the food compositionis dispensed to form a layer, the food composition has sufficientrigidity and strength to support its own weight and the weight ofsubsequently deposited layers thereon to allow the formation of amulti-layer object without incurring an excessive shape change. Such aphysical state of sufficient rigidity and strength is a non-solid state,but could be a thick paste or slurry like a cake mix or consistentliquid chocolate. The method also includes operating a computer andmachine controller for generating control signals in response tocoordinates of the design of this object and for controlling theposition of the dispensing head relative to the support member inresponse to the control signals to control dispensing of the foodcomposition to construct a 3-D shape of this object. Specifically, thedispensed food composition is deposited in multiple layers which stackup and adhere to one another to build up a 3-D shape in a non-solidstate.

Drive means such as servo or stepper motors are provided to selectivelymove the support member and dispensing head relative to each other in apredetermined pattern along a direction parallel to an X-Y plane definedby first (X) and second (Y) coordinate axes as the food composition isbeing dispensed to form a layer. After one layer is built, thedispensing head and the support member are moved away from each other bya predetermined layer thickness. The same procedures of moving anddispensing are then repeated to form each successive layer with eachlayer having its own characteristic shape and dimensions. Suchmechanical movements are preferably achieved through drive signalsinputted to the drive motors for the support member and the dispensinghead from a computer or controller/indexer/servo regulated by acomputer. The computer may have a CAD/CAM software to design and createthe object to be formed. Specifically, the software is utilized toconvert the 3-D shape of an intended object into multiple layer data,which is transmitted as drive signals through a controller to the drivemotors. Each individual computer-generated layer can have its own shapeand thickness. It is the combination and consolidation of these layersthat form a complete 3-D shape of the object.

The food composition is composed of at least one liquid ingredient(e.g., water, ethanol, vinegar, fruit juice, liquid chocolate, cookingoil, malt syrup, honey, butter, margarine, cream, liquid cheese, eggcontent, or a combination thereof) and a primary object body-buildingfood material preferably in powder, granule, or small chip form. Thisprimary body-building material may be selected from the group consistingof flour, starch, yeast, meat, vegetable, fruit, pepper, salt, flavor,chocolate, sugar, syrup, salt, butter, margarine, cheese, andcombinations thereof.

The liquid ingredient serves one important purpose in the present SFFmethod. It serves as a vehicle or medium in which other ingredients canbe dissolved or dispersed to make a fluent paste or slurry. Hence, thisingredient is preferably a liquid at room temperature or can be easilyheated to become a liquid. Such a fluent food composition can be readilydispensed through an orifice of a dispensing head. After the foodcomposition is dispensed to build a layer, however, the food compositionmust be in a physically rigid state in which the material viscosity orrelaxation modulus is sufficiently large that this food composition willno longer undergo any significant deformation (shape or dimensionchange) when other parts of a layer or successive layers are built. Theprimary body building material may contain food ingredients in powder orsmall granule form so that the mixture as a paste is sufficiently thick,i.e., with sufficient rigidity. The mixture remains in a paste ornon-solid state during the entire object-building process.

In the case of a primary body-building food material not soluble in aparticular liquid, this body-building material may be dispersed (but notdissolved) in this liquid; e.g., some flour and yeast powder dispersedin water. A third ingredient (such as yam starch) may be added to serveas an adhesive which will glue together the powder particles to helpmaintain the shape of the 3-D object when part of water graduallyvaporizes after the object is made.

In one preferred embodiment, for instance, an extruder or gear pump maybe used to deliver a food composition to a dispensing head. Amultiple-channel colorant-feeding module is disposed at the nozzle tofeed selected food colorants into the food composition-hosting chamberof the dispensing head just before the food composition is discharged.Such an arrangement makes it more responsive to change from one colorantto another on demand. Alternatively, one may use a plurality ofdispensing heads with each head set up to dispense a food compositioncontaining a different colorant.

Applications and Advantages of the Present Invention

More Versatile and Realistic Rapid Prototyping of Food Products:

The present invention provides a simple yet versatile method for rapidlyproducing a model for a food item. Due to the versatility of thismethod, a user of this method is free to choose a liquid ingredient anda primary body-building food material from a wide spectrum ofcompositions. A wide range of body-building food materials may becombined to form a food item with a desired combination of chemical(e.g., taste), physical and aesthetic properties. A model or prototypefood item may be designed and made to be similar in both composition andshape to the final food product if mass production of this item isdesired. Hence, the prototype can be fully evaluated to verify thetaste-function-form of a food item before mass production begins. Thiscould help eliminate the possibility of producing a large number of foodobjects only to find out that these objects do not meet therequirements.

For Fabrication of Food Objects of Intricate Shape or One-of-a-KindItems without Using a Mold or Die:

The present invention provides a cost-effective food fabrication method.Most of the current food processing techniques are not capable of makingfood objects of a complex geometry. SFF concepts provide effectiveapproaches to the production of complex shapes without object-specifictooling or human intervention. Cost-effective freeform fabricationtechniques will significantly enhance the attractiveness of a food item.This new technology will permit the production of custom designed foodobjects on demand. For instance, it can be used to fabricate a cake thatis designed by a customer. Every birthday cake can have a different andunique (one-of-a-kind) shape, different material ingredients, and/or adifferent color pattern.

Simple and Less Expensive Fabrication Equipment Design:

The presently invented method makes it possible to have a simpledispensing head design. For instance, polymer melts (including naturalpolymers) are normally highly viscous and, hence, difficult to pump,extrude, or eject out of a small orifice due to a high capillaritypressure. The incorporation of a liquid ingredient will make it easierto prepare a flowable food composition, normally without a need to heatthe nozzle. The nozzle design can be much less complex. No exotic, fancyor complex fluid delivery device is required. This will also make thecontrol and operation of the present SFF system simple and reliable.

These and other advantages of the invention will become readily apparentas one reads through the following description of preferred embodimentsand the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A perspective view of an apparatus capable of building a 3-Dobject layer by layer.

FIG. 2 Schematic of a layer manufacturing system for the fabrication ofa food object.

FIG. 3 (a) The dispensing head has a flat bottom and an orifice, (b) Thegap between the nozzle flat bottom 32 and a preceding layer 36 serves tocontrol the thickness of a new layer being deposited.

FIG. 4 A dispensing head having a plurality of nozzles.

FIG. 5 A flow chart showing the sequence of creating the 3-D object by aCAD software program, establishing layer-by-layer database by layeringsoftware, and sending out motion-controlling signals by a computer tothe drive motors through a motion controller.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate one preferred embodiment of the presentlyinvented method for making a three-dimensional (3-D) food object. Thismethod begins with creation of a computer-aided design (a drawing,image, geometry representation) of a three-dimensional object using acomputer. This method further involves the operation of a system thatincludes computer software and control hardware (e.g., motioncontroller/indexer/servo 14). The system includes a support member 16 bywhich the object is supported while being constructed. The system alsohas a dispensing head 18 for dispensing a strand (22 in FIG. 2 or 34 inFIG. 3b) of food composition in a fluent state. This food compositionincludes a liquid ingredient that helps to make the composition in aflowable state while still residing in a chamber 26 of the dispensinghead 18. The food composition in this chamber is supplied,intermittently or continuously, from a material delivery means 20 suchas a screw extruder, gear pump, metering pump, positive displacementvalve, solenoid-controlled valve, and air pump (pneumatically operatedpump).

The method requires the food composition after being discharged from thedispensing head to be in a rigid but non-solid state in which multiplelayers of the food composition can be stacked up one upon another(without incurring an excessive shape change) to form a 3-D shape ofthis object. The method also includes operating a computer 12 forgenerating control signals in response to coordinates of the design ofthis object and operating the controller/indexer 14 for controlling theposition of the dispensing head relative to the support member inresponse to the control signals. During the steps of moving thedispensing head relative to the support member, the dispensing head 18is also controlled to dispense the food composition, continuously orintermittently, for constructing a 3-D shape of the object 28 whilesupported with the support member 16.

The flowable food composition is composed of a liquid ingredient, aprimary object body-building food material, and other optionaladditives. This food composition is capable of achieving a rigid stateimmediately after being dispensed out of an orifice 30 at the bottomportion 32 of the dispensing head 18 to deposit onto a surface of amoveable support member 16 (FIG. 3). The process begins with thedeposition of a first layer (e.g., 38 in FIG. 3b) prior to deposition ofa second layer (e.g., 36) and subsequent layers (e.g., 34 in FIG. 3b).These steps are repeated until all constituent layers of the 3-D objectare deposited. At this moment of time, the fabricated 3-D shape remainsin a non-solid state. This 3-D shape (e.g., a cake mix) may then besubjected to a further treatment (baking in an oven) at a later stage tochange the physical or chemical state of the object (becoming a piece ofedible cake). A food composition is composed of at least a liquidingredient, at least a primary body-building food material (that can beselected from a group consisting of starch, flour, pepper, meat,vegetable, fruit, chocolate, sugar, syrup, salt, butter, margarine,cheese, cream and combinations thereof) and possibly other additives.

Food Compositions:

The discharged food composition that comes in contact with the supportmember or a previous layer should preferably meet two conditions. Thefirst condition is that this composition must have a sufficiently highviscosity to prevent excessive flow (or spreading) when being deposited;this is required in order to achieve a good dimensional accuracy. Thesecond condition is that the newly discharged material should preferablybe able to adhere to a previous layer. These two conditions can be metby discharging the following three major types of food compositions:

Type I:

The food composition of Type 1 contains a primary body-building foodmaterial that is soluble in the volatile ingredient: e.g., starchsoluble in water. Water keeps the food composition in a fluent stateinside the chamber of the dispensing head. The body-building materialmay contain a viscosity enhancing agent (e.g., meat granules) and/orother additives so that the resulting mixture is thick and consistentand will not flow or spread up excessively when the mixture is depositedto form individual layers.

EXAMPLE 1

Corn starch (10 grams) was dissolved in approximately 100 cc of water atapproximately 60° C. to form a solution. Additional amount of starch(another 30 grams) was added to the solution; this additional amount ofstarch powder was dispersed in water and “swollen” by water, but not inwater. This slurry-like food composition was extruded through anextrusion nozzle to deposit onto a wood-based support member layer bylayer. A hot melt applicator system (Slautterback Model “Little Squirt”with an electrically controlled dispensing head and extrusion nozzle)supplied by Astro Packaging Corp. (Placentia, Calif., USA) was used todispense the food composition.

EXAMPLE 2

Corn starch (10 grams) was dissolved in approximately 100 cc of water atapproximately 70° C. to form a solution. Approximately 10 grams offinely ground meat granules was added to this solution to increase theconsistency (viscosity) of the solution. Such a mixture made a thickpaste. This tooth paste-like food composition was extruded through anextrusion-type nozzle to deposit onto a wood-based support member (akitchen chopping board).

EXAMPLE 3

Potato starch (10 grams) was dissolved in approximately 100 cc of waterand 20 cc of cooking wine at approximately 70° C. to form a solution.Additional amount of starch was added to the solution, which wasdispersed but not totally dissolved in this mixture of water andalcohol. This slurry-like food composition was extruded through asyringe-type nozzle to deposit onto a polyethylene-based support memberto build a 3-D shape layer by layer. The incorporation of alcoholaccelerated the thickening or rigidization process of the foodcomposition, which was a multi-material mixture.

Type II:

The food composition of Type II contains a primary body-buildingmaterial in the form of discrete particles that can be dispersed, butnot dissolved in the liquid ingredient, e.g., beacon powder dispersed inwater. Water keeps the food composition in a fluent state inside thechamber of a dispensing head, but the food composition is thick andconsistent (with a sufficiently high viscosity to become rigid). Theresulting shape would be fragile due to a lack of cohesive bonds betweenindividual beacon particles. Therefore, a certain amount of edibleadhesive (e.g., yam starch) may be dispersed between particles forhelping to bond the particles together.

EXAMPLE 4

Baking wheat flour (40 g), sugar (5 g), corn syrup (3 g) and yeast (0.7g) were mixed in 40 grams of water at 50° C. to form a paste. Thispaste-like food composition was extruded through a syringe-type nozzleto deposit onto a polyethylene-based support member of a 3-D objectmaker. A 3-D shape was formed layer by layer by using a freeformfabrication machine designed and installed in our lab. The sugar, yeastand corn syrup made the paste relatively thick and they resided betweenwheat flour particles, helping to bond together these particles whensome amount of water was removed. The fabricated 3-D shape was furtherheated in a kitchen oven to activate the baking process.

EXAMPLE 5

A piece of baked cake (approximately 10 grams) was ground in a foodprocessor into a powder form. This cooked cake powder was then dispersedin a mixture of chocolate syrup (10 g), sugar (2 g), cooking wine (3 g)and water (15 g) at 50° C. to form a paste. This paste-like foodcomposition was used to serve as cake topping. This mixture was extrudedthrough a nozzle to deposit onto a piece of pre-baked cake sitting on atop surface of a wood support member in a 3-D object maker for forming a3-D intricate-shape topping layer by layer.

Type III:

A sol-gel material (e.g., an edible natural polymer gel composed of alightly cross-linked network of chains with small molecules occupyinginterstices between these chains). These small molecules can be fromwater, cooking oil, wine, etc. The sol-gel can be formulated to haveproper flowability inside the food composition-hosting chamber of anozzle, yet having good viscosity and rigidity after being dispensed.The gelation process of the food composition may be controlled in such afashion that no gelation occur to any significant extent inside thechamber of a dispensing nozzle. Once discharged onto the support memberor a previous layer, however, the gelation process may be advancedfurther to increase the viscosity of the food composition so that it hasan adequate rigidity.

EXAMPLE 6

A variety of natural polymer powders, such as lotus root and cornstarch, may be well dispersed in warm water to produce a paste for beingreadily transported to a dispensing head. For instance, a tea spoon oflotus root powder containing approximately 10% by weight sugar was addedto a cup (approximately 10 cc) of warm water at 50° C. Additional waterat a higher temperature (95-100° C.) was then added just prior to thedischarging step to activate the fast gelation process. A hot air blowerwas used to accelerate the gelation process after the mixture wasdischarged from the dispensing head to construct a 3-D object layer bylayer. This food composition was naturally glued to a previous layer,yet would not flow to any significant extent in this highly gelledstate.

Processes and Needed Hardware:

The process involves intermittently or continuously dispensing thefluent food composition through an orifice 30 of a dispensing head 18 todeposit onto a surface of a support member 16 (FIG. 2). During thisdispensing procedure, the support member and the dispensing head aremoved (preferably under the control of a computer 12 and acontroller/indexer 14) with respect to each other along selecteddirections in a predetermined pattern on an X-Y plane defined by first(X-) and second (Y-) directions and along the Zdirection perpendicularto the X-Y plane. The three mutually orthogonal X-, Y- and Z-directionsform a Cartesian coordinate system. These relative movements areeffected so that the food composition can be deposited essentially pointby point and layer by layer to build a multiple-layer object accordingto a computer-aided design (CAD) drawing of a 3-D object.

In a preferred embodiment, the bottom (e.g., 32 in FIG. 3a) of thedispensing head 18 is made to be flat so that this flat portion actslike a “doctor's blade” to slightly compress down the food compositionwhen being discharged from the orifice against the substrate. The word“substrate” in the present context refers to the surface of the supportmember when the first layer is being built or to the surface of theimmediate preceding layer when the second or subsequent layers are beingdeposited. The gap between the substrate and this doctor's blade ispreferably made to be slightly smaller than the diameter of the strandof food composition being dispensed. This would help to produce a layerwith a smooth surface.

In one preferred embodiment, an optional heating provision (e.g.,heating elements) is attached to, or contained in, the nozzle to controlthe physical and chemical state of the food composition; e.g., to helpmaintain it in a fluent state. A temperature sensing means (e.g. athermocouple) and a temperature controller can be employed to regulatethe temperature of the nozzle. Heating means are well known in the art.

Advantageously, the dispensing head may be designed so that thedischarge orifice can be readily removed and replaced with anotherorifice of a different size. Such an adjustable tip is desirable becausean operator may choose to use different food compositions to buildportions of an object or different components.

Referring again to FIG. 1, the support member 16 is located in close,working proximity to, but at a predetermined initial distance from, thedispensing head 18. The upper surface of the support member preferablyhas a flat region sufficiently large to accommodate the first few layersof deposited food composition. The support member and the dispensinghead are equipped with mechanical drive means for moving the supportmember relative to the movable dispensing head in three dimensions along“X,” “Y,” and “Z” axes in a predetermined sequence and pattern, and fordisplacing the nozzle a predetermined incremental distance relative tothe base member. This can be accomplished, for instance, by allowing thesupport member and the dispensing head to be driven by three linearmotion devices powered by three separate stepper motors.

As an example, schematically shown in FIG. 1 is a support member withtwo slots 42A,42B extending along the “X” axis and being guided by twocorresponding tracks 43A,43B of a supporting base plate 44. A steppermotor 41, attached to said supporting base plate 44, is 25 employed tomove the support member 16 along the “X” axis. The supporting base plate44 is, in turn, provided with a second linear motion mechanism, drivenby a second stepper motor to provide movements along the “Y” axis. Forinstance, the supporting base member 44 can be directed to slide on twoparallel slots 46A,46B, extending along the “Y” axis, of anotherreversibly slidable base plate 48. This supporting base plate 48 isfurther provided with another drive means to provide “Z”-axis movements.Any similarly configured mechanical means can be utilized to move thebase plate 48 reversibly in the vertical direction (along the “Z” axis).Simplistically shown at the lower portion of FIG. 1 is a protruded rail50 (attached to, or integral with, base plate 48), which slidesvertically on a “Z”-axis slot of a post 52. The post is connected to orintegral with a sturdy base 54. Z-axis movements are effected todisplace the nozzle relative to the support member and, hence, relativeto each layer deposited prior to the start of the formation of eachsuccessive layer. This will make it possible to form multiple layers ofmaterial composition of predetermined thickness, which build up on eachother sequentially as the material composition solidifies after beingdischarged from the orifice. Instead of stepper motors, many other typesof drive means can be used, including linear motors, servo motors,synchronous motors, D.C. motors, and fluid motors.

As another preferred embodiment of the present invention, the apparatusused for the method may comprise a plurality of dispensing heads eachhaving flow-passage means (chamber or channel) therein connected to adispensing orifice at one end thereof. Each additional nozzle isprovided with a separate supply of a different food composition, andmeans for introducing this food composition into the flow-passage sothat the food composition is in a fluent state just prior to discharge.

Another embodiment of the present invention involves using amultiple-nozzle apparatus as just described. However, at least onenozzle is supplied with a material for depositing a support structurefor supporting those features of the 3-D object that cannot supportthemselves (e.g., overhangs and isolated islands). The support materialused may be another food composition that, if necessary, can be easilyremoved at a later stage.

An example of such a multiple-nozzle apparatus is schematically shown inFIG. 4, wherein a food composition is introduced into a container 170,optionally pushed by a pressurizing means 172, to pass through a channel174 and a regulating valve 176 and enter a chamber 178. In this chamber,the food composition is allowed to be pumped by a metering gear pump 180to enter a flow passage 182. The fluid flow is then split into multiplechannels 184A, 184B, each leading into a nozzle 188A or 188B. Eachadditional nozzle may comprise flow-passage means 190A or 190B, a tipwith a discharge orifice of a predetermined size therein, and valvemeans 186A or 186B, preferably disposed near the tip. Each additionalnozzle may be provided with a separate supply of colorant-containingmaterials from a container 192A or 192B through valve means 196A or 196Binto the passage 190A or 190B, where the colorant is mixed with the foodcomposition delivered from the gear pump 180. It may be noted that eachadditional nozzle may be in flow-communication with more than onecolorant-feeding channel. Each nozzle may take turn to deposit amaterial of a different color to build a portion of the object 200supported by a platform 206. A support structure 204 is built to supportan unsupported feature 202 (e.g., the bottom part of a cup handle shapemember). This example is presented to illustrate how different foodcompositions or substantially the same composition but of differentcolors may be dispensed to form a multi-color food object. Ediblecolorants are commercially available.

There are many commercially available metering and dispensing nozzlesthat are capable of dispensing the food compositions in the presentlyinvented method. Examples include various two-component dispensingdevices such as PosiDot® from Liquid Control Corp. (7576 Freedom Ave.,North Canton, Ohio) and Series 1125 Meter-Mix-Dispense systems fromAshby-Cross Company, Inc. (418 Boston Street, Topsfield, Mass.). A hotmelt applicator system may also be used; e.g., Slautterback Model“Little Squirt” with an electrically controlled dispensing head andextrusion nozzle, supplied by Astro Packaging Corp. (Placentia, Calif.,USA). Any of such prior art dispensing nozzles can be incorporated as apart of the dispensing head used in the presently invented method todeposit food compositions when and where needed.

Computer-Aided Design and Process Control:

A preferred embodiment of the present invention is a solid freeformfabrication method in which the execution of various steps may beillustrated by the flow chart of FIG. 5. The fabrication process beginswith the creation of a mathematical model (e.g., via computer-aideddesign, CAD), which is a data representation of a 3-D object. This modelis stored as a set of numerical representations of layers which,together, represent the whole object. A series of data packages, eachdata package corresponding to the physical dimensions and shape of anindividual layer, is stored in the memory of a computer in a logicalsequence.

In one preferred approach, before the constituent layers of a 3-D objectare formed, the geometry of this object is logically divided into asequence of mutually adjacent theoretical layers, with each theoreticallayer defined by a thickness and a set of closed, nonintersecting curveslying in a smooth two-dimensional (2-D) surface. These theoreticallayers, which exist only as data packages in the memory of the computer,are referred to as “logical layers.” This set of curves forms the“contour” of a logical layer or “cross section”. In the simplestsituation, each 2-D logical layer is a plane so that each layer is flat,and the thickness is the same throughout any particular layer. However,this is not necessarily so in every case, as a layer may have anydesired curvature and the thickness of a layer may be a function ofposition within its two-dimensional surface. The only constraint on thecurvature and thickness function of the logical layers is that thesequence of layers must be logically adjacent. Therefore, in consideringtwo layers that come one after the other in the sequence, the mutuallyabutting surfaces of the two layers must contact each other at everypoint, except at such points of one layer where the corresponding pointof the other layer is void of material as specified in the object model.

As summarized in the top portion of FIG. 5, the data packages for thelogical layers may be created by any of the following methods:

(1) For a 3-D computer-aided design (CAD) model, by logically “slicing”the data representing the model,

(2) For topographic data, by directly representing the contours of theterrain,

(3) For a geometrical model, by representing successive curves whichsolve “z=constant” for the desired geometry in an x-y-z rectangularcoordinate system, and

(4) Other methods appropriate to data obtained by computer tomography(CT), magnetic resonance imaging (MRI), satellite reconnaissance, laserdigitizing, line ranging, or other reverse engineering methods ofobtaining a computerized representation of a 3-D object.

An alternative to calculating all of the logical layers in advance is touse sensor means to periodically measure the dimensions of the growingobject as new layers are formed, and to use the acquired data to help inthe determination of where each new logical layer of the object shouldbe, and possibly what the curvature and thickness of each new layershould be. This approach, called “adaptive layer slicing”, could resultin more accurate final dimensions of the fabricated object because theactual thickness of a sequence of stacked layers may be different fromthe simple sum of the intended thicknesses of the individual layers.

The closed, nonintersecting curves that are part of the representationof each layer unambiguously divide a smooth two-dimensional surface intotwo distinct regions. In the present context, a “region” does not mean asingle, connected area. Each region may consist of several island-likesubregions that do not touch each other. One of these regions is theintersection of the surface with the desired 3-D object, and is calledthe “positive region” of the layer. The other region is the portion ofthe surface that does not intersect the desired object, and is calledthe “negative region.” The curves that demarcate the boundary betweenthe positive and negative regions, and are called the “outline” of thelayer. In the present context, the material composition is allowed to bedeposited in the “positive region” while, optionally, other ediblematerial may be deposited in certain parts or all of the “negativeregion” in each layer to serve as a support structure.

As a specific example, the geometry of a three-dimensional object may beconverted into a proper format utilizing commercially availableCAD/Solid Modeling software. A commonly used format is the stereolithography file (.STL), which has become a de facto industry standardfor rapid prototyping. The object image data may be sectioned intomultiple layers by a commercially available software program. Each layerhas its own shapes and dimensions, which define both the positive regionand the negative region. These layers, each being composed of aplurality of segments, when combined together, will reproduce a shape ofthe intended object.

In one embodiment of the present invention, the method involvesdepositing an easily removable material in all of the negative regionsin each layer to serve as a support structure. This support structuremay be removed at a later stage or at the conclusion of theobject-building process. The presence of a support structure (occupyingthe negative region of a layer), along with the object-building material(the positive region), will completely cover a layer before proceedingto build a subsequent layer.

As another embodiment of the present invention, the 3-D object makingprocess comprise additional steps of (1) evaluating the data files ofthe CAD drawing representing the intended object to locate anyunsupported feature of the object and (2) responsive to this evaluationstep, determining a support structure for the unsupported feature. Thiscan be accomplished by, for instance, (a) creating a plurality ofsegments defining the support structure, (b) generating programmedsignals corresponding to each of the segments defining this supportstructure in a predetermined sequence; and (c) operating a separatematerial deposition device, in response to these programmed signals forbuilding the support structure.

When a multi-material or multi-color object is desired, these segmentsare preferably sorted in accordance with their material compositions orcolors. This can be accomplished by taking the following procedure: Whenthe stereo lithography (.STL) format is utilized, the geometry isrepresented by a large number of triangular facets that are connected tosimulate the exterior and interior surfaces of the object. The trianglesmay be so chosen that each triangle covers one and only one materialcomposition or color. In a conventional .STL file, each triangular facetis represented by three vertex points each having three coordinatepoints, (x₁,y₁,z₁), (x₂,y₂,z₂) and (x₃,y₃,z₃), and a unit normal vector(i,j,k). Each facet is now further endowed with a material compositionor color code to specify the desired food ingredient or colorant. Thisgeometry representation of the object is then sliced into a desirednumber of layers expressed in terms of any desired layer interfaceformat (such as Common Layer Interface or CLI format). During theslicing step, neighboring data points with the same material compositionor color code on the same layer may be sorted together. These segmentdata in individual layers are then converted into programmed signals(data for selecting dispensing heads and tool paths) in a proper format,such as the standard NC G-codes commonly used in computerized numericalcontrol (CNC) machinery industry. These layering data signals may bedirected to a machine controller which selectively actuates the motorsfor moving the dispensing head with respect to the support member,activates signal generators, drives the food material supply means (ifexisting) for the dispensing head, drives the optional vacuum pumpmeans, and operates optional temperature controllers, etc. It should benoted that although .STL file format has been emphasized in thisparagraph, many other file formats have been employed in differentcommercial rapid prototyping and manufacturing systems. These fileformats may be used in the presently invented system and each of theconstituent segments for the object geometry may be assigned a materialcomposition code if an object of different material compositions orcolors at different portions is desired.

The three-dimensional motion controller is electronically linked to themechanical drive means and is operative to actuate the mechanical drivemeans (e.g., those comprising stepper motors in FIG. 1) in response to“X”, “Y”, “Z” axis drive signals for each layer received from the CADcomputer. Controllers that are capable of driving linear motion devicesare commonplace. Examples include those commonly used in a millingmachine.

Numerous software programs have become available that are capable ofperforming the presently specified functions. Suppliers of CAD/SolidModeling software packages for converting CAD drawings into .STL formatinclude SDRC (Structural Dynamics Research Corp. 2000 Eastman Drive,Milford, Ohio 45150), Cimatron Technologies (3190 Harvester Road, Suite200, Burlington, Ontario L7N 3N8, Canada), Parametric Technology Corp.(128 Technology Drive, Waltham, Mass. 02154), and Solid Works (150 BakerAve. Ext., Concord, Mass. 01742). Optional software packages may beutilized to check and repair .STL files which are known to often havegaps, defects, etc. AUTOLISP can be used to convert AUTOCAD drawingsinto multiple layers of specific patterns and dimensions.

Several software packages specifically written for rapid prototypinghave become commercially available. These include (1) SOLIDVIEWRP/MASTER software from Solid Concepts, Inc., Valencia, Calif.; (2)MAGICS RP software from Materialise, Inc., Belgium; and (3) RAPIDPROTOTYPING MODULE (RPM) software from Imageware, Ann Arbor, Mich. Thesepackages are capable of accepting, checking, repairing, displaying, andslicing .STL files for use in a solid freeform fabrication system.MAGICS RP is also capable of performing layer slicing and convertingobject data into directly useful formats such as Common Layer Interface(CLI). A CLI file normally comprises many “polylines” with each polylinebeing an ordered collection of numerous line segments. These and othersoftware packages (e.g. Bridgeworks from Solid Concepts, Inc.) are alsoavailable for identifying an unsupported feature in the object and forgenerating data files that can be used to build a support structure forthe unsupported feature. The support structure may be built by aseparate fabrication tool or by the same dispensing head that is used tobuild the object.

A company named CGI (Capture Geometry Inside, currently located at 15161Technology Drive, Minneapolis, Minn.) provides capabilities ofdigitizing complete geometry of a three-dimensional object. Digitizeddata may also be obtained from computed tomography (CT) and magneticresonance imaging (MRI), etc. These digitizing techniques are known inthe art. The digitized data may be re-constructed to form a 3-D model onthe computer and then converted to .STL files. Available softwarepackages for computer-aided machining include NC Polaris, Smartcam,Mastercam, and EUCLID MACHINIST from MATRA Datavision (1 Tech Drive,Andover, Mass. 01810).

Another preferred embodiment of the present invention is a method formaking a 3-D object as defined in any of the above-described processes,yet with the following additional specifications: (a) the dischargeorifice tip of the nozzle has a substantially planar bottom surfacebeing maintained at a predetermined gap distance from the supportmember, (b) the planar bottom surface of the tip is maintainedsubstantially parallel to both the first layer and the plane of thesupport member while a second layer of food composition is beingdeposited onto the first layer from the orifice. These two requirementsare specified so that the planar bottom surface of the orifice tipprovides a shearing effect on the top surface of the second layer tothus closely control the absolute location of successive layers withrespect to the support member. The orifice acts essentially like a“doctor's blade”. This action also serves to avoid any accumulativeerror in layer build-up, and to maintain a smooth layer surface.

Sensor means may be attached to proper spots of the support member orthe material dispensing head to monitor the dimensions of the physicallayers being deposited. The data obtained are fed back periodically tothe computer for re-calculating new layer data. This option provides anopportunity to detect and rectify potential layer variations; sucherrors may otherwise cumulate during the build process, leading tosignificant part inaccuracy. Many prior art dimension sensors may beselected for use in the present apparatus.

As indicated earlier, the most popular file format used by allcommercial rapid prototyping machines is the .STL format. The .STL fileformat describes a CAD model's surface topology as a single surfacerepresented by triangular facets. By slicing through the CAD modelsimulated by these triangles, one would obtain coordinate points thatdefine the boundaries of each cross section. It is therefore convenientfor a dispensing head to follow these coordinate points to trace out theperimeters (peripheral contour lines) of a layer cross section. Theseperimeters may be built with selected food composition patterns. Theseconsiderations have led to the development of another embodiment of thepresent invention. This is a method as set forth in the above-citedprocess, wherein the moving step includes the step of moving thedispensing head and the support member relative to one another in adirection parallel to the X-Y plane according to a first predeterminedpattern to form an outer boundary of one selected food composition or adistribution pattern of different food compositions onto the supportmember. The outer boundary defines an exterior surface of the object.

Another embodiment of the present invention includes a process as setforth in the above paragraph, wherein the outer boundary defines aninterior space in the object, and the moving step further includes thestep of moving the dispensing head and the support member relative toone another in one direction parallel to the X-Y plane according to atleast one other predetermined pattern to partially or completely fillthis interior space with a selected food composition. The interior spacedoes not have to have the same food material composition as the exteriorboundary. The interior space may be built with food compositions of aspatially controlled material composition comprising one or moredistinct types of ingredients. The food compositions may be deposited incontinuously varying concentrations of distinct types of materials. Thismethod may further comprise the steps of (1) creating a geometry of theobject on a computer with the geometry including a plurality of segmentsdefining the object and material compositions to be used; and (2)generating program signals corresponding to each of these segments in apredetermined sequence, wherein the program signals determine themovement of the dispensing head and the support member relative to oneanother in the first predetermined pattern and at least one otherpredetermined pattern.

At the conclusion of 3-D shape formation process, most of the liquidingredient still remains in this shape. The present method may includeadditional steps of removing a portion or a majority of the residualliquid ingredient after the shape is constructed. In some cases, thestarting material composition may contain un-activated materials such aswheat flour and yeast or baking powder. Hence, the resulting 3-D shapemay not be ready for consumption. The method then could further includeadditional steps of heat treating (e.g., baking) the shape to become anedible food object.

We claim:
 1. A freeform fabrication method for making athree-dimensional food object from a design created on a computer,comprising: (a) providing a support member by which said object issupported while being constructed; (b) operating a material dispensinghead for dispensing a continuous or intermittent strand of a foodcomposition in a fluent state onto said support member, said foodcomposition comprising a liquid ingredient and a primary body-buildingfood material and said strand of food composition, once dispensed,rapidly reaching a physical state of a rigidity and strength sufficientfor permitting said food composition to be self-supporting while beingbuilt up layer by layer into a three-dimensional shape in a non-solidstate; and (c) operating control means for generating control signals inresponse to coordinates of said design of said object created on thecomputer and controlling the position of said dispensing head relativeto said support member in response to said control signals to controldispensing of said food composition to construct said object whilesupported with said support member.
 2. The method of claim 1, furtherincluding additional step of applying a heat treatment to saidconstructed three-dimensional object.
 3. The method of claim 1 whereinsaid dispensing head receives said food composition from an extrusiondevice selected from the group consisting of an extruder, a meteringpump, a positive displacement valve, an pneumatically operated valve, asolenoid-controlled valve, and combinations thereof.
 4. The method ofclaim 1 wherein said control means include servo means for indexing andpositioning said dispensing head relative to said support member.
 5. Themethod of claim 4 wherein said servo means provide indexing andpositioning in at least two dimensions.
 6. The method of claim 1 whereinsaid support member comprises a pre-fabricated food base member ontowhich said 3-D food object is deposited.
 7. The method of claim 1wherein said dispensing head includes an orifice through which saidstrand of food composition is dispensed and controlled to have aprescribed cross-sectional profile in accordance with the object beingconstructed.
 8. The method of claim 1 wherein said dispensing headincludes profile control means through which said food composition isdispensed in a generally continuous strand and by which a continuousstrand profile of said strand is controlled according to the objectbeing constructed.
 9. The method of claim 1 wherein said foodcomposition comprises a liquid ingredient selected from the groupconsisting of water, ethanol, vinegar, liquid chocolate, cooking oil,malt syrup, honey, butter, margarine, cream, liquid cheese, egg content,and combinations thereof.
 10. The method of claim 1 wherein said foodcomposition comprises a primary body-building food material in powder,granule, or small chip form; said material selected from the groupconsisting of flour, starch, meat, vegetable, fruit, chocolate, sugar,syrup, salt, butter, margarine, cheese, and combinations thereof. 11.The method of claim 10 wherein said primary body-building food materialcontains wheat flour dispersed in said liquid ingredient.
 12. The methodof claim 10 wherein said primary body-building food material contains astarch dissolved in said liquid ingredient.
 13. The method of claim 10wherein said food composition comprises a colorant.
 14. The method ofclaim 1 wherein said dispensing head has an orifice at a generally flatbottom portion of said dispensing head and said flat bottom portioncompresses down and deforms said strand of food composition when beingdispensed from said orifice to produce a layer having a flat and smoothsurface layer.
 15. The method of claim 1, wherein said food compositioncomprises a cooked food material.
 16. The freeform fabrication method ofclaim 1, wherein said steps of operating a material dispensing head andoperating control means comprising moving said dispensing head and saidsupport member relative to one another in a plane defined by first andsecond directions and in a third direction orthogonal to said plane toform said food composition into a three-dimensional object in anon-solid state.
 17. The freeform fabrication method of claim 16,wherein said primary body-building food material comprises discreteparticles and an edible adhesive composition which are both dispersed insaid liquid ingredient; said adhesive composition can be later activatedto bond said discrete particles together.
 18. The freeform fabricationmethod of claim 16, wherein said primary body-building food materialcomprises starch dissolved in said liquid ingredient and wheat flourdispersed in said liquid ingredient.
 19. The freeform fabrication methodof claim 16, wherein said food composition includes a sol-gel materialcontaining a volatile ingredient.
 20. The freeform fabrication method ofclaim 16, wherein said liquid ingredient includes a mixture of at leasttwo liquids.
 21. The freeform fabrication method of claim 16, wherein anadditional dispensing head is used to deposit a support structure for anun-supported feature of said object.
 22. The freeform fabrication methodof claim 16, wherein said moving step includes the steps of moving saiddispensing head and said support member relative to one another in adirection parallel to said plane to form a first layer of said foodcomposition on said support member, moving said dispensing head and saidsupport member away from one another in said third direction by apredetermined layer thickness distance, and dispensing a second layer ofsaid food composition onto said first layer while simultaneously movingsaid dispensing head and said support member in said direction parallelto said plane, whereby said second layer adheres to said first layer.23. The freeform fabrication method of claim 22, further including thesteps of forming multiple layers of said food composition on top of oneanother by repeated dispensing of said food composition as saiddispensing head and said support member are moved relative to oneanother in one direction parallel to said plane, with said dispensinghead and said support member being moved away from one another in saidthird direction by a predetermined layer thickness after each precedinglayer has been formed.
 24. The freeform fabrication method of claim 16,further including the steps of: creating a geometry representation ofsaid three-dimensional object on a computer, said geometryrepresentation including a plurality of segments defining said object;generating programmed signals corresponding to each of said segments ina predetermined sequence; and moving said dispensing head and saidsupport member relative to one another in response to said programmedsignals.
 25. The freeform fabrication method of claim 16, wherein saidmoving step includes the step of moving said dispensing head and saidsupport member relative to one another in a direction parallel to saidplane according to a first determined pattern to form an outer boundaryof said food composition on said support member, said outer boundarydefining an exterior surface of said object.
 26. The freeformfabrication method of claim 25, wherein said outer boundary defines aninterior space in said object, and said moving step further includes thestep of moving said dispensing head and said support member relative toone another in said direction parallel to said plane according to atleast one other predetermined pattern to fill said interior space withsaid food composition.
 27. The freeform fabrication method of claim 25,further including operating another dispensing head for dispensing adifferent food material composition, and wherein said outer boundarydefines an interior space in said object, and said moving step furtherincludes the step of moving said another dispensing head and saidsupport member relative to one another in one direction parallel to saidplane according to at least one other predetermined pattern to fill saidinterior space with said different food material composition.
 28. Thefreeform fabrication method of claim 26, further comprising the steps ofcreating a geometry representation of said three-dimensional object on acomputer, said geometry representation including a plurality of segmentsdefining said object, and generating programmed signals corresponding toeach of said segments in a predetermined sequence, wherein saidprogrammed signals determine said movement of said dispensing head andsaid support member relative to one another in said first predeterminedpattern and said at least one other predetermined pattern.
 29. Themethod of claim 16, further including additional step of applying a heattreatment to said constructed three-dimensional object.
 30. The methodas set forth in claim 16, further comprising periodically measuringdimensions of the object being built by means of dimension sensor means;determining the thickness and outline of individual layers of said foodcomposition deposited in accordance with a computer aided designrepresentation of said object; said computer being operated to calculatea first set of logical layers with specific thickness and outline foreach layer and then periodically re-calculate another set of logicallayers after comparing the dimension data acquired by said sensor meanswith said computer aided design representation in an adaptive manner.31. The freeform fabrication method of claim 1 wherein the steps ofoperating a material dispensing head including dispensing a strand of afirst food composition in a fluent state to a predetermined locationabove said support member and dispensing a second strand of a secondfood composition in a fluent state to at least another location abovesaid support member; said first and second strands of food compositions,once dispensed, rapidly reaching a physical state of a rigidity andstrength sufficient for permitting said food compositions to beself-supporting while being built up layer by layer into athree-dimensional shape in a non-solid state; and during said dispensingsteps, moving said material-dispensing head and said support memberrelative to one another in a plane defined by first and seconddirections and in a third direction orthogonal to said plane to formsaid first and second food compositions into a three-dimensional shapeof said object in a non-solid state.
 32. The method of claim 31, furtherincluding additional step of applying a heat treatment to saidconstructed three-dimensional shape.
 33. The method as set forth inclaim 26 wherein said interior space is deposited with a spatiallycontrolled food composition comprising two or more distinct types ofbody-building food materials.
 34. The method as set forth in claim 26wherein said interior space is deposited with a food composition incontinuously varying concentrations of distinct materials inthree-dimensional object space to form a spatially controlled foodcomposition object.
 35. The method as set forth in claim 34 wherein saiddistinct types of materials are deposited at discrete locations inthree-dimensional part space to form a spatially controlled foodmaterial composition object.